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Aftermarket portioning valve


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1 hour ago, acfortier said:

I don't see 4 lines coming out of the prop. valve. I see 3 total lines from the picture? Also, you have a picture of the rear where it splits to each wheel, so it seems that each rear wheel isn't on its own from the prop. valve?


Agreed. Looks like a normal setup. To the OP: tighten your those flares or reflare if necessary and you should be good to go. Everything else looks fine. 

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23 hours ago, Whitaker717 said:

Well I think that’s how it is. It’s in the shop so I can’t look. There are 4 lines coming out of that portioning valve. I assumed one went to each wheel. 

 

No.

 

Check again, when you get the truck back. You should have one hard line that runs to a termination above the rear axle. From there, there should be a single rubber hose that connects to a tee fitting mounted to the axle tube. From that tee fitting there's a hard line to each rear brake cylinder.

 

You should not have separate lines from the proportioning valve to each rear wheel. Which is what you wrote.

 

The proportioning valve should have two lines going into it (the two on top, from the master cylinder), and three coming out of it. Here's what it looks like inside:

 

 

Brake_Blocks_002_R1.jpg

 

And remember, you have a TJ (or maybe an XJ or ZJ) proportioning valve. That's very different from the stock MJ front distribution block, which looks similar on the outside but which does NOT have any proportioning function.

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Try tightening the fittings first. If you have to reflare you will need to make a “double” flare. The flare has to fit the shape of the seat that it will be screwed into. If you look carefully at eagles picture you will see the conical seat in each outlet/inlet of that prop valve. 
 

This is what te flare should look like when finished:

639E8CAB-BE0A-4EC0-B5A0-523EC720F171.jpeg.dc5970bd619ae2d58262cfa6908aa3ba.jpeg

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16 hours ago, Whitaker717 said:

Another question Eagle, are there any better flares to use or are they all the same. That’s where it seemed the fluid was coming from. Could I have caused those flares leaking somehow?

 

There are two types of flares -- the SAE double flare shown in the post above, and the "bubble" flare. MJs use the SAE double flare.

 

The brake line layout on your truck isn't any different or more complicated than what's found on 90% of vehicles built since about 1960 (or whenever the industry changed to separate circuits for the front and rear wheels). Your brake system is not stock. The OEM Comanche system, with the rear height-sensing proportioning valve, trips up a lot of people who are new to MJs.

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  • 2 weeks later...

So quick update on the valve, according to the mechanic I take it to he said the fluid was leaking out of the electrical connector on the top of the valve. Has anyone ever had that happen? He said he just took out the electrical connector because he can’t find one anywhere. Is this normal. This guy is a great mechanic but man these brake issues make me nervous. 

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1 hour ago, Whitaker717 said:

Does it hurt or help to eliminate it? 

Best to replace as is a safety issue. However, mine has been unplugged since the wire melted due to the bad sensor, which only went bad cause of the hissing sound from my brake pedal. So with a spongy pedal telling the sensor to tell me I have an issue. :doh: I don't know about you but I like to stop when I need to and I will be ensuring all my parts are replaced and in good working order before I go far. :eek:

With that said, I have been driving it for about a year like that, so you could still drive it, as you have been anyways. :dunno: So once it's replaced you shouldn't have to worry about it and thats peace of mind. :scholar:

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2 hours ago, Whitaker717 said:

Does it hurt or help to eliminate it? 

 

Technically, it's illegal.

 

Look again at the cutaway photos I posted. If there's brake fluid coming out of the port for the warning light switch, that means one or both of the O-rings for the shuttle valve has failed.

 

Replace the proportioning valve.

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